Alkali hydrolyzable polymeric materials preventing sponge expansion

ABSTRACT

A compressed sponge situated in a gaseous environment is provided with an alkali hydrolyzable polymeric material impregnated therein to prevent said sponge from expanding both before, and for a predetermined time period after, it is contacted with an aqueous alkaline composition.

United States Patent 1191 Sullivan [45] Oct. 28, 1975 ALKALI HYDROLYZABLE POLYMERIC 3,649,331 3/1972 Peterson 117/98 x MATERIALS PREVENTING SPONGE i EXPANSION 3,767,297 10/1973 352/130 [75] Inventor: Charles I. Sullivan, Melrose, Mass. 3,772,975 11/1973 325/78 X 3,778,140 12 1973 352/130 [731 Asslgneei {2 Corpmatwmcambndge, 3,785,725 1/1974 Batter 352/78 ass.

[22] Filed: No 19, 1973 Primary Examiner-1 E. Willis, Jr.

Attorney, Agent, or FirmSusan M. Cooke; Esther A. [21] Appl. No.. 416,764, H. Hopkins [52] US. Cl. 428/304; 428/500; 428/532 [57] v ABSTRACT [51] Int. Cl? C08J 9/40; C08J 9/42 A o d n t d [58] Field of Search.... 117/98, 165, DIG. 9, 143 A; C e "T a gaseous ment 1s prov1ded w1th an alkali hydrolyzable poly- 161/405, 264/321 menc matenal 1mpregnated therem to prevent sa1d [56] References Cited sponge frorn expanoing both l oef ore, and for a rede- T D S ATES PATENTS termmed period afte r, 1t 1s contacted w1th an aqueous a a me composmon. 3,420,363 1/1969 Blickensderfer 264/321 X 3,425,965 2/1969 Skochdopole 264/321 x 7 Clam, N0 Drawmgs ALKALI HYDROLYZABLE POLYMERIC MATERIALS'PREVENTING SPONGE EXPANSION BACKGROUND OF THE INVENTION The present invention is concerned with a mechanism for preventing expansion of a compressed sponge situated in a gaseous environment both before, and for a predetermined time period after, it is contacted with an aqueous alkaline composition. This invention is particularly concerned with the use of such a mechanism at the film processing station in a class of photographic film cassettes.

As described in U.S. Pat. No. 3,615,127 issued Oct. 26, 1971 to E. H. Land and U.S. Pat. No. 3,641,896 issued Feb. 15, 1972 to R. B. Downey, cassette systems in which a film strip need not be removed during its exposure, processing andprojection include a processing station where processing fluid may be applied to a film strip to develop said film after it has been exposed. Processing fluid stored in a container within the cassette is dispensed onto the film through a nozzle at the processing station across which the exposed film strip is transported.

Upon development the film strip is ready for projection, but because the cassette is designed so that the film must pass by the processing station every time it is projected, the nozzle outlet must be closed off to prevent any more processing fluid from reaching the film and impairing the developed images carried on it. In aforementioned U.S. Pat. No. 3,641,896 this accomplished by means of a flexible strip which slides over the nozzle outlet. A similar device comprising a valve plate is employed to close off the nozzle outlet in the cassette system described in U.S. Pat. No. 3,785,725 issued to J. F. Batter, Jr. et al which provides for substantially automatic processing of the film when it is appropriately transported by the processing station.

To better ensure that no processing fluid will leak out when the nozzle outlet is closed off, a seal may be provided between the nozzle and closure plate. Such a seal is employed on the surface of the closure plate in U.S. Pat. No. 3,772,976 issued to J. F. Batter, Jr. et a1. As disclosed therein, a thin layer of material which preferably swells upon. contact with the processing fluid is coated on the valve surface which comes into contact with the nozzle outlet when the valve is moved over the nozzle. Anothersealing device located on the closure valve is described in U.S. Pat. application Ser. No. 416,762 now U.S. Pat. No. 3,868,716 entitled Compressed Open Cell Foam Sealing Assembly, commonly assiged and filed simultaneously with this application by J. S. Stella and I. S. Lippert. The sealing mechanism described for this cassette system comprises a compressed open cell foam saturated with a material which coagulates the processing fluid. A layer of this saturated foam is coated onto the valve surface which comes into contact with the nozzle outlet when the valve is displaced over the nozzle after processing of thefilm strip. When contacted with processing fluid, the foam expands to better seal off the nozzle outlet and releases the coagulating material saturated therein. Since .this material coagulates processing fluid upon contact, it can help prevent processing fluid from flowing onto the film.

Another way of preventing fluid leakage from the nozzle outlet after processing is to provide a material within the fluid container which expands over the nozzle intake so as to absorb any fluid in the vicinity. For example, a compressed sponge could be located near the nozzle intake. When processing fluid flows through the intake and out of the nozzle, the fluid would contact the sponge. As the sponge absorbed the fluid, it would expand over the intake opening where it could absorb all fluid in that area and thereby prevent any more fluid from flowing out of the nozzle. If such a system is vented to the atmosphere it is important that the sponge be fairly insensitive to humidity so that it will not absorb moisture from the air and swell prematurely. Furthermore, even when contacted with the processing fluid the sponge must not expand too rapidly or else the required amount of fluid will not be able to flow through the nozzle and onto the film being processed.

Unfortunately, sponges are often comprised of hydrophilic material so that they generally do absorb water vapor from the atmosphere and swell. Furthermore, ordinary compressed sponges also tend to expand too rapidly in the photographic cassette systems described above so as to prevent the requisite amount of processing fluid from being dispensed upon the film strip. It is therefore necessary to employ some means of insuring compression of the sponge until it is contacted with the processing fluid and of delaying sponge expansion across the nozzle intake opening until the amount of fluid required for processing pruposes has been allowed to pass into the nozzle. As described in U.S. Pat. application Ser. No. 416,763 now U.S. Pat. No. 3,882,526 entitled Photographic Processing Apparatus Employing Delayed Action Expandable Sponge and filed simultaneously with this application by J. A. Stella and I. S. Lippert, such as mechanism might encompass a material impregnated in the compressed sponge, the bonds of this material being strong enough to hold the sponge together and prevent its expansion before, and for a predetermined time period after, the material is contacted with an aqueous alkaline composition such as the processing fluid.

OBJECTS OF THE INVENTION It is therefore a primary object of this invention to prevent substantially any expansion of a compressed sponge situated in a gaseous environment before, and for a predetermined time period after, contact with an aqueous alkaline composition Another object of this invention is to provide a material which can be impregnated into a sponge and can prevent the sponge when compressed and situated in a gaseous environment from expanding to any substantial degree before, and for a predetermined time period after, contact with an aqueous alkaline composition.

A further object is to provide an alkali hydrolyzable polymeric material which can be impregnated into a sponge for prevention of said sponge expansion. A still further object is to provide such a polymeric material which is substantially nonhydrolyzable and nondegradable by atmospheric water vapor.

SUMMARY OF THE INVENTION It has now been found that certain alkali hydrolyzable polymeric materials impregnated in a compressed sponge situated in a gaseous environment can prevent substantially any expansion of that sponge before, and for a predetermined time period after, said material has been contacted with an aqueous alkaline composition When employed in the sponge material of a photographic film cassette system such as that disclosed in aforementioned U.S. application Ser. No. 416,763, polymeric materials which prevent sponge expansion for a time period ranging from 15 seconds to several minutes after contact with the processing fluid have been found useful.

DETAILED DESCRIPTION OF THE INVENTION The sponge expansion delay mechanism of this invention comprises a compressed sponge situated in a gaseous environment and impregnated with an alkali hydrolyzable polymeric material preventing substantially any expansion of said sponge before, and for a predetermined time period after, said polymeric material is contacted with an aqueous alkaline composition.

Alkali hydrolyzable polymeric materials found useful in impregnating the sponge material of a photographic film cassette system such as that disclosed in the above noted US Pat. application Ser. No. 416,763 lose their bonding strength, and thus their ability to prevent sponge expansion, in a time period ranging from 15 seconds to several minutes after contact with alkali. In this cassette system the sponge is encased in a container vented to the atmosphere. Any polymeric material which is used to impregnate the sponge should therefore be substantially nonhydrolyzable and nondegradable by atmospheric water vapor in order to prevent premature swelling of the sponge. When the sponge is situated in a gaseous environment excluding substantially all water vapor, the polymeric material s resistance to water vapor need not be considered.

Polymeric materials found especially useful in cassette systems such as the one noted above include an interpolymer of ,B-cyanoethyl acrylate, butyl acrylate, methyl methacrylate and 2-sulfoethyl methacrylate (40/36/24/] .5 by weight), an interpolymer of hydroxypropyl methacrylate, butyl acrylate, methyl methacrylate and 2-sulfoethyl methacrylate (40/36/24/l.5 by weight), an interpolymer of butyl acrylate, hydroxypropyl methacrylate, methacrylic acid and 2-sulfoethyl methacrylate (85/10/2/3 by weight) and an interpolymer of butyl acrylate, B-cyanoethyl acrylate, methacrylic acid and 2-sulfoethyl methacrylate (85/ /2/3 or 91/41/2/3 or 89/6/2/3 by weight). To better control the amount of polymer deposited and subsequent drying of the sponge, emulsion polymers such as these may be mixed with an appropriate diluent such as water or acetone in which the sponge can be soaked so as to impregnate it. For example, the sponge may be impregnated with polymer by immersion in a 2% solids mixture of the first interpolymer named above and acetone.

Although naturally occurring and manufactured sponges comprised of many different types of materials may be utilized in the products of this invention, sponges comprised of cellulosic materials are especially preferred when utilized in a photograhic film cassette such as that described in aforementioned US. Pat. application Ser. No. 416,763. Sponges having a pore size ranging from one-sixty-fourth in. to one-eighth in. with an average pore size of about one-sixteenth in. are particularly useful in this system. It is important that none of the pores be too large since an opening might remain in the expanded sponge which would provide an avenue for the escape of processing fluid.

After the sponge has been impregnated with the polymeric material it may then be compressed and dried so as to vaporize the liquid phase in the polymeric emulsion used to impregnate the sponge. This may be accomplished, for example, by partially drying the sponge, compressing it and completing the drying procedure; by completely drying the sponge and then compressing it; or by compressing the sponge while it is still wet and then drying it. Sponges having a compression ratio (thickness when expanded/thickness when compressed) in the range of 5/1 to 20/1 may be utilized. in such a cassette system. Sponges in the above described system typically range from .015 to .060 inches thick when compressed, preferably being about .030 inches thick, and can expand between ten and twenty times their compressed size.

Although the sponge expansion delay mechanism of this invention is described in connection with photographic film cassette systems, such a mechanism could be utilized in any situation where it was necessary to automatically stop the flow of an aqueous alkaline composition. Since other substitutions and changes may of course be made in this product without depar'ting from the scope of the disclosed invention, it is intended that all matters contained in the foregoing description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A compressed sponge situated in a gaseous environment and impregnated with an alkali hydrolyzable polymeric material substantially nonhydrolyzable and nondegradable by water vapor, said polymeric material preventing substantially any expansion of said sponge before, and for a predetermined time period after, said polymeric material is contacted with an aqueous alkaline composition.

2. The product of claim 1 wherein said aqueous alkaline composition is a photographic processing fluid, said sponge when compressed is approximately .030 inches thick and said time period after contact with aqueous alkaline composition is in the range of l5='sec.- ends to several minutes.

3. The product of claim 2 wherein said polymeric material is an interpolymer of B-cyanoethyl acrylate, butyl acrylate, methyl methacrylate and 2-sulfoethyl methacrylate.

4. The product of claim 2 wherein said polymeric material is an interpolymer of hydroxypropyl methacrylate, butyl acrylate, methyl methacrylate and 2-sulfoethyl methacrylate.

5. The product of claim 2 wherein said polymeric material is an interpolymer of B-cyanoethyl acrylate, butyl acrylate, methacrylic acid and 2-sulfoethyl methacrylate.

6. The product of claim 2 wherein said polymeric material is an interpolymer of hydroxypropyl methacrylate, butyl acrylate, methacrylic acid and 2-sulfoethyl contacted with an aqueous alkaline composition. 

1. A COMPRESSED SPONGE SITUATED IN A GASEOUS ENVIRONMENT AND IMPREGNATED WITH AN ALKALI HYDROLYZABLE POLYMERIC MATERIAL SUBSTANTIALLY NONHYDROLYZABLE AND NONDEGRADABLE BY WATER VAPOR, SAID POLYMERIC MATERIAL PREVENTING SUBSTATIALLY ANY EXPANSION OF SAID SPONGE BEFORE, AND FOR A PREDETERMINED TIME PERIOD AFTER, SAID POLYMERIC MATERIAL IS CONTACTED WITH AN AQUEOUS ALKALINE COMPOSITION.
 2. The product of claim 1 wherein said aqueous alkaline composition is a photographic processing fluid, said sponge when compressed is approximately .030 inches thick and said time period after contact with aqueous alkaline composition is in the range of 15 seconds to several minutes.
 3. The product of claim 2 wherein said polymeric material is an interpolymer of Beta -cyanoethyl acrylate, butyl acrylate, methyl methacrylate and 2-sulfoethyl methacrylate.
 4. The product of claim 2 wherein said polymeric material is an interpolymer of hydroxypropyl methacrylate, butyl acrylate, methyl methacrylate and 2-sulfoethyl methacrylate.
 5. The product of claim 2 wherein said polymeric material is an interpolymer of Beta -cyanoethyl acrylate, butyl acrylate, methacrylic acid and 2-sulfoethyl methacrylate.
 6. The product of claim 2 wherein said polymeric material is an interpolymer of hydroxypropyl methacrylate, butyl acrylate, methacrylic acid and 2-sulfoethyl methacrylate.
 7. A compressed sponge situated in a gaseous environment excluding substantially all water vapor and impregnated with an alkali hydrolyzable polymeric material, said polymeric material preventing substantially any expansion of said sponge before, and for a predetermined time period after, said polymeric material is contacted with an aqueous alkaline composition. 